/Engine/Source/Runtime/Engine/Classes/Particles/ParticleSystemComponent.h
Get the beam target strength
true EmitterIndex and TargetIndex are valid - OutTargetStrength is valid false EmitterIndex or TargetIndex is invalid - OutTargetStrength is invalid
virtual bool GetBeamTargetStrength ( int32 EmitterIndex, int32 TargetIndex, float & OutTargetStrength ) const